P0717

Symptoms

• Illuminated check engine light / transmission warning lamp
• harsh or delayed shifts
• limp-mode operation
• transmission slipping or shifting problems
• decreased fuel efficiency
• possible engine stalling at idle.

Probable causes

• 1) Failed input/turbine speed sensor (internal element produces no voltage; failure from internal electrical problems, contamination by metal particles in the fluid, or wear). 2) Wiring/connector faults: corroded pins
• broken wires
• loose connector clips
• or a single high-resistance joint dropping the signal below the TCM detection threshold. 3) Power/ground faults: blown fuse
• faulty power feed
• high-impedance ground. 4) Low or contaminated transmission fluid. 5) Internal transmission damage (e.g. worn turbine shaft) preventing the sensor from detecting rotation. 6) TCM/PCM fault (least common).

Diagnostic steps

1. Connect a scan tool, retrieve P0717 and related codes, and monitor input speed sensor live data.
2. Check transmission fluid level and condition (should be red, not burnt); correct low or contaminated fluid first.
3. Visually inspect the sensor and its connector for damage, contamination, corrosion, and loose pins; inspect the harness for breaks or chafing.
4. With ignition/engine running, test the sensor power feed - sources cite approximately 5 V (+/-0.5 V) on the power lead; no voltage points to a power-supply/fuse fault.
5. Check sensor ground continuity to chassis; sources cite resistance above 0.5 ohm as a compromised ground path.
6. Measure sensor resistance and compare to the service manual value (sources cite a typical 300-600 ohm range, service manual value prevails).
7. Verify sensor output with a multimeter or oscilloscope while the vehicle rotates the input shaft (in gear); no output with good power/ground and wiring = replace the sensor.
8. If sensor, wiring and power are all good, suspect internal transmission damage or the TCM; diagnostic procedures vary by manufacturer, so follow vehicle-specific service information.